Acta Crystallographica Section A

Foundations of Crystallography

Volume 52, Part 3 (May 1996)

research papers

Acta Cryst. (1996). A52, 438-449 [ doi:10.1107/S0108767396000773 ]

The Non-Resonant Magnetic X-ray Scattering Cross Section of MnF₂. 2. High-Energy X-ray Diffraction at 80keV

J. Strempfer, T. Brückel, U. Rütt, J. R. Schneider, K.-D. Liss and T. Tschentscher

Abstract: Results of high-energy non-resonant magnetic X-ray diffraction experiments performed on the model system MnF₂ at a photon energy of 80 keV are presented. A surprisingly high peak intensity of the magnetic 300 reflection of 13000 photons s^-1 in the three-crystal mode and 19000 photons s^-1 in the two-crystal mode, with a peak-to-background ratio of 230:1 and 10:1, respectively, has been achieved. At 80 keV, the penetration depth is 7 mm. When the path length of the beam through the crystal is varied, the effect of volume enhancement of the intensity diffracted by magnetic reflections is demonstrated. The Q dependence of the magnetic and the charge Bragg reflections has been measured and agrees well with theory. The measurement of the temperature dependence of the sublattice magnetization allows a very accurate determination of the critical exponent = 0.333 (3) and the Néel temperature T_N = 67.713 (2) K. Finally, the multiple charge scattering is discussed, which is very pronounced for the magnetic reflections of MnF₂.